Wireless Signal-Based Image Matching for Mobile Geolocation
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Solution Overview
Problem
Mobile visual search programs on devices like cellular telephones and PDAs face challenges due to computational intensity and reliance on incomplete or inaccurate location information, which affects the identification of image features and geolocation matching.
Innovation Solution
A method and system that utilize signal strength information from wireless access points to estimate the location and orientation of a wireless user device, comparing captured images against a database of geo-located images to refine location estimates and provide accurate pose information, including the use of a front end module and cell match module for image processing and matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mobile visual search programs use traditional image analysis methods, then image feature identification can be achieved, but computational intensity increases and processing time extends
Solution Approach 1:
The patent divides the image database into multiple cells based on geographic location. Each cell contains images and their associated visual features. This segmentation allows the system to search only within relevant geographic cells rather than the entire database, significantly reducing computational load while maintaining identification accuracy
Solution Approach 2:
The patent pre-computes and stores visual features (corners, edges, lines, histograms) for all images in the database during an indexing phase. This preliminary action allows the matching process to compare pre-extracted features rather than analyzing raw images during query processing, dramatically improving processing speed
2Measurement precision
If mobile visual search programs rely on device location information, then geolocation matching can be performed, but location accuracy decreases when GPS is unavailable or inaccurate
Solution Approach 1:
The patent introduces wireless access points and base stations as intermediary objects for location determination. Instead of relying solely on GPS, the system uses signal strength measurements from these intermediaries to estimate device location. This intermediary approach provides reliable location information in environments where GPS is unavailable or inaccurate
Solution Approach 2:
The patent replaces the mechanical/GPS-based location system with a wireless signal-based location system. By substituting GPS with wireless access point triangulation using signal strength, the system achieves reliable location determination in urban canyons, indoors, and other GPS-challenged environments
3Measurement precision
If the system searches the entire image database for matches, then comprehensive matching can be achieved, but processing time increases significantly
Solution Approach 1:
The patent segments the image database into geographic cells and uses the estimated device location to identify only the relevant cell for searching. This spatial segmentation ensures that the search is both comprehensive (covering all images in the relevant area) and efficient (excluding images from unrelated areas)
Solution Approach 2:
The patent applies local quality by focusing computational resources on the specific geographic cell where the device is located. Instead of uniform searching across the entire database, the system concentrates processing power on the local region of interest, improving both speed and relevance of results
Data Source
AI summary
Aspects of the disclosure pertain to matching a selected image/photograph against a database of reference images having location information. The image of interest may include some location information itself, such as latitude/longitude coordinates and orientation. This location information may be based on information obtained when the user's device interacts with base stations or other access points in a wireless communication network, such as signal strength information. The location information is used as an estimated location. The image of interest and the estimated location are used to select one or more cells to match the image against. Each cell may have multiple images and an index. The image is compared against specific cells, and if a match is found, a front end server identifies the correct location and orientation of the received image, and may correct errors in the estimated location of the user device.